Electric circuit interrupter



y 1947. R. s. BENNETT ELECTRIC CIRCUIT INTERRUPTER Filed June 29, 1943 2Sheets-Sheet l Inventor Ralph S. Bennett,

u A I 1K I I I I I I I I r I I I I I I I I! His Attorney.

y 1947- Rls. BENNETT 2,421,236

ELECTRIC CIRCUIT INTERRUPTER Filed June 29, 1943 2 Sheets-'Shet 2 F7 .6.v. ,54 7/ I Invento%-:

Ralph S. Bennett,

y )VM 6? ,J AAQQ I Hi5 Attorne \mw, partly in section, of the PatentedMay 27, 194"! ELECTRIC CIRCUIT INTERRUPTER- Ralph S. Bennett,Pittsfield,

General Electric Company,

New Yor':

Mass, assignor to a corporation of Application June 29, 1943, Serial No.492,691

Claims. 1

My invention relates to electric circuit interrupters and. moreparticularly to circuit interrupters of the rluid blast tym whereinpressure is utilized to effect a blast of arc-extinguishing orinsulating liquid through a break in the cl"- cuit to be interrupted.Specifically, my invention is an improvement on U. S. Letters Patent2,049,318, Prince, granted July 28, 1936, and assigned to the sameassignee as the present application.

It is an object of my invention to provide a new andimproved fluid blastcircuit interrupting means.

It is another object of my invention to provide a fuse cut out type ofcircuit interrupting device operating on the oil blast principle inwhich two arcs in series are produced substantially simultaneously sothat the oil blast produced may become effective before the current andpressure have increased to dangerously high values.

Still. another object of my invention is to provide a fuse cut out typof circuit interrupting device operating on the oil blast principle inwhich two arcs in series are produced substantially simultaneously uponthe blowing of a single fusible element.

Further objects and advantages of my invention will become apparent asthe following desorlption proceeds and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had to theaccompanying drawings in which Fig.1 is an elevational view, partly insection, of a circuit interrupting device embodying my invention; Fig. 2is a top circuit interrupter Fig. 1 with the cover of the casingremoved; Fig. 3 is a side elevational view. partly in section, of aportion of the fuse carrier of Fig. 1; Figs. 4 and 5 the portion of thefuse carrier shown in Fig. 3, and Fig. 6 illustrates a modification ofmy invention.

Although my invention may have application generally in connection withfluid blast circuit interrupters, I have chosen to illustrate itspecifically as applied to the well known form of oilfilled fuse cut outdisclosed in United States Patents 1,195,790, 1,203,316, and 1,248,090.

As shown in the drawings the oil fuse cutout embodying my invention andgenerally indicated at H! comprises a cyindrical container or tank steelso as to be suflill, preferably formed of are exploded perspective viewsof ciently strong to withstand the pressures ge. ated therein undercertain conditions. i is provided with a drain plug E2 in the portionthereof. The interior of tank it is erably provided with a liner l3 ofsuitable insu lating material. A suitable cover it preferably formed ofcast iron is threadedly attached to tank I I as indicated at l5.

Bolted or otherwise suitably fastened to the cover H of oil fuse cutouti0 is a suitable ring 1'6 of insulating material which depends from. thecover so as to be almost wholly contained i l casing H. The insulatingring l8 supports flat stationary contacts l1. As best indicated in 2,these flat stationary contacts I! are self-align. ing by virtue or thepin and slot connections indicated at l8 and I9 respectively. Furthermore, each of these contacts is spring biased by means of a helicalspring 20 tending to push fiat contacts ll toward the center ofinsulating l6. Two contacts H are provided which are mounteddiametrically opposite one another with. respect to cylindrical tank IIand each of these contacts is connected by suitable conductors 2i and 22with an external electrical circuit through suitable entrance bushings23, as shown in Fig. 1. Tank II is filled with a suitable dielectric,such as oil for example, to the level indicated in Fig. l.

The portion of the oil-filled cutout Ill described thus far may besubstantially identical with the cutout disclosed in Patent 1,248,090referred to above and forms no part of my present invention.Consequently, it has only been briefly de scribed since a detaileddescription thereof is available in the above mentioned United StatesLetters Patent.

The cover it of oil fuse cutout I0 is provided with a central opening 24through which is in serted a fuse carrier generally indicated at 25.This fuse carrier comprises a metal cap 26 having ventilating orbreathing openings 21 therein. A rectangular opening 26' is provided sothat any handy lever may be inserted to assist in turning the fusecarrier. The top of this cap is provided with a hood 28. Cap 26 isprovided with an annular flange 29 to suitably seat on an upturnedflange 30 surrounding the opening 24 in cover M. A suitable gasket 3imay be in terposed between flanges 29 and 30 for sealing purposes. Cap26 also includes a depending flange 32 extending into the opening 24 ofcover it. A suitable plug such as 33, preferably formed of 9. treatedwood, is provided with an upper portion of cylindrical form which" fitssnugly into an opening or recess in depending flange 32 of cap and ispinned thereto by a. suitable pin or rivet 33'. This portion of woodplug 33 inserted in the lower portion of cap 26is provided with two flatsides such as 34 to provide breathing or vent ing passageways 35 fromwithin the casing of cutout 16 to the exterior through the vent openings21. As is disclosed in the above mentioned Patent 1,195,790 the cover 14and the cap 26 are provided with suitable locking means so that flanges29 and 30 may be maintained in sealing engagement with one anotherthrough gasket 31 when the fuse carrier 25 is in the position indicatedin Fig. 1. This locking means is not shown in the drawing.

Fuse carrier 25 further includes supporting means for the movablecontacts to be described hereinafter comprising a generally cylindricalmember 36 of insulating material having an annular recess 36 provided inthe upper portion thereof to accommodate wood plug 33. Suitablyfastened. to the lower portion of movable contact supporting means aremovable contacts i and Movable contact 31 has a downwardly extendingportion 39 while contact 38 has an up-- wardly extending portion 46,both of which are suitably fastened to contact supporting member 36 byfuse link attachment screws 4 I. Flat headed screws 42 extend throughmovable contacts 31 and 38 into member 36, thereby firmly supporting thecontacts 31 and 38 on member 36. These contacts are somewhat concave inform with respect to the portion thereof engaging member 36 and areadapted to make electrical contact with fiat contacts ll. Ihe circuit atcontacts 3'! and I7 and contacts 38 and i1 is made and broken byrotating fuse carrier 25 in a manner clearly described in the abovementioned United States Letters Patent.

Surrounding the upper portion of movable contact support 36 is a guidesupporting cylinder 44 formed of insulating material which in turn sup--ports insulating guides 45 best shown in Figs. 3 and 4. Insulatingguides 45 are attached to guide supporting member 44 by means of screwsor other suitable supporting means 46 and 61. These screws aresufilciently long to also threadedly engage not only the openings 46 incylinder 45 but also the openings 49 in the upper part of movablecontact supporting member 36. Furthermore, the screws 61 are long enoughto engage the openings 50 in wood plug 33 indicated in Fig. 4, therebymaking the fuse carrier 25 in effect a unitary structure. The insulatingguide members 45 which are preferably formed of insulating material areadapted to engage cooperating slots (not shown) in the cover member Hadjacent opening 24 to insure that fuse carrier 25 is inserted only in apredetermined manner with the contacts 31 and 38 thereof rotated to aposition out of line with stationary contacts 11. After the fuse carrier25 is fully inserted the guide members 45 are substantially free of thecooperating slots (not shown) in cover member l4 so that fuse carrier 25may be rotated and contacts 37 and 38 may then engage stationary fiatcontacts ll. At the same time the locking means referred to above anddisclosed in the above mentioned United States Letters Patent 1,195,790comes into play to lock fuse carrier 25 in position so that flanges 29and 30 are in sealing engagement with the gasket 3! therebetwe'en.

In order to provide a fuse arrangement embodying the oil blast principlein which two arcs are produced substantially instantaneously and serieswith each other upon the blowing of a single fusible element, I haveprovided within contact supporting member 36 a metallic pressure chamberor reservoir 52 which comprises a cylindrical member 53 and end members54 and 55 each having an opening such as 56 and 5 respectively, therein.The metallic chamber 52 comprising members 53, 56 and 55 is supportedwithin cylindrical member 36 by annular insulating supporting means 58and 55 which are fastened by suitable insulating screws 66 to member 36provided with cooperating openings 61. A fuse link is provided generallyindicated at 62 comprising a fusible element 63 having suitableterminals 64 at either end thereof connected to flexible cable loops 65and 65. Flexible cable loops 65 and 65' are adapted to be slipped overfuse links supporting screws 6| to support the fuse link 62 in theposition shown in Fig. 1. Loop 65 is made less flexible than loop 65 asone means for controlling the length of the arc and thereby to generatemore gas and thus to provide greater pressure in the one portion than inthe other so as to aid in directing the blast in the dc sired direction.By making cable 65' less flexible than cable 65 the lower arc ispermitted to grow longer faster than the upper arc and hence produce anupwardly directed oil blast. If desired, a suitable strain wire 66 maybe connected in parallel with fusibl element 63 between terminals 64.

Upon the occurrence of predetermined current conditions fusible element63 will melt and an arc will occur between terminals 64. However, due tothe prorimity of the walls of reservoir chamber 52 to arcs, one tomember 56 and the other to member 55, will. occur substantiallysimultaneously. Since the opening in member 58 is larger and shorterthan the opening in member 59, the lower arc will tend to producegreater pressure and thus an oil blast from the reservoir chamber 52,which blast is forced through the upper arc to extinguish the same.Also, the opening 56 in member 54 is smaller than the opening 5'! inmember 55 so that the lower arc will be longer and tend to producegreater pressure. Suitable Openings 6! are provided in member 36 topermit free escape of the oil blast to the upper oil level, whereas theblasting of fluid from the lower end of the lower opening 51 isrestricted by the greater head of oil as provided by the verticalarrangement at openings 56 and 51 and reservoir chamber 52 on thevertically inserted fuse carrier 25. Where necessary, a furtherrestriction of the blast from the lower end of opening 51 can beprovided by the addition of suitable baffles or the like. Similarly,member 36 is provided with an opening 66 through which the flexiblecable 65 may extend to engage electrically the contact 38. In order thatguide supporting cylinder 46 will not interfere with the operation ofoil blast openings 61 or opening 63 it is provided with recesses 66 and10. It should be underst )od that my invention is not limited to thespecific means or combination of means for directing the fluid blast andthe direction of said blast as herein described, since other means foraccomplishing this will suggest themselves to those skilled in the art.

From th above description it will be obvious that the length of thefusible element 63 and the length of the pressure chamber 52 may be soadjusted that when the fusible element ruptures the arc will tend tojump at once from upper fusible terminal 64 to the edge of pressurechamber 52 surrounding opening 56 and from the edge "by the lower arcwill blast. the fluid in pressure chamber 52 through the upper arctoextinguish it and thereby interrupt the circuit through fuse '-I havefound it desirable to construct the mewtallic chamber or oil reservoircomprising mem- ;bers 53, 54 and 55 of steel since steel affordsappreciableresistance to current-flow, thereby tending to limitthecurrent belowthe values which might otherwise beattained. This isdesirableandhelpful in extinguishing the arc.

In viewyof the detailed description included above, the operation of thefuse cutout operating on the oil blast principle embodying my inventionwill be obvious and no further discussion will be included here. It willbe observed that the fuse carrier 25 embodying my invention may replacethe fuse carrier of prior art fuses of the .type similar to cutout l0.

The metallic chamber or oil reservoir comprising members 53, .54, and 55may be constructed to have short gaps between the respective members soas to produce short arcs at an advantageous position within the oilreservoir to produce a blast of fluid through both of the other arcs. InFig. 6 I have illustrated the metallic pressure chamber of Figs. 1 and 5with the parts thereof separated by insulating washers H and 12 whichmay be constructed of fiber or the like.

-In this way the oil in the reservoir may be used to the greatestpossible extent.

While I have shown and described a particular embodiment of myinvention, it will be obvious -.to those skilled in the'art that variouschanges and modifications may be made without departing from myinvention in its broader aspects and I therefore aim in the appendedclaims to cover all-such changes and modifications as fall within thetrue spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In an electric circuit interrupting device of the fluid blast type,an arc chamber of conducting material containing an arc-extinguishingliquid, means defining a pair of openings one at each end of said arechamber, and a fuse link including a fusible element having a singlerupturable section extending through said openings so that said fusibleelement is in said are cham- :ber immersed in said liquid, said fusibleelement being so arranged that upon rupture of said fusible element twoarcs in series are produced substantially simultaneously between said.fuse link and said first mentionedmeanswith one of said arcs producing afluid blast to extinguish said other arc.

2. In an electric circuit interrupting device of the fiuid blast type, afuse carrier, an arc chamber of conducting material supported on saidcarrier, means defining a. pair of openings one at each end of said arechamber, a fuse link including a fusible element supported by saidcarrier and extending through said openings with said fusible element insaid are chamber, said fusible element and said arc chamber being soarranged that upon rupture of said fusible element two arcs in seriesare produced substantially simulblast type comprising an arc chambercontaining an arc-extinguishing liquid, and a fusible element having asingle rupturable section immersed and arranged to rupture in saidliquid in said chamber. said chamber and said fusible element being soarranged that upon rupture of said fusible ele- .ment two, arcs inseries are producedsubstantially simultaneously, and means for at leastpartially confining the. escape of the fluid blast caused by one of saidarcs to produce a fluid blast to extinguish said other arc.

- 4.- An electric circuit interrupter of the fluid blast type comprisingan arc chamber containing an arc-extinguishing liquid, and a fusibleelement immersed and arranged to rupture in said liquid in said chamber,said chamber and saidfusible element being so arranged that upon ruptureof said fusible element two arcs in series are produced substantiallysimultaneously, and means for increasing the arc gas pressure created byone of said arcs to provide a fluid blast to extinguish said other arc.

. with electrically conductive material, and a single circuit openingmeans immersed and arranged to draw an arc in said liquid in saidchamber, said electrically conductive lining and said circuit openingmeans being so arranged that upon the drawing of the arc, two arcs inseries are produced substantially simultaneously with. one of saidarcsproducing a fluid blast from the reservoir portion of said chamber toextinguish said other arc.

6. An electric circuit interrupter of the fluid blast type comprising anarc chamber containing an arc extinguishing liquid, an electricallyconducting member in said chamber, and a single circuit opening meansimmersed and arranged during a circuit opening operation to produce anarc in said liquid in said chamber, said electrically conducting memberand said circuit opening meansbeing so arranged that upon I theproduction of said arc, two arcs in series are produced substantiallysimultaneously with one of said arcs producing a fluid blast toextinguish said other arc.

7. An electric circuit interrupter of the fluid blast type comprising anarc chamber containing an arc-extinguishing liquid, said are chambercomprising means defining two relatively small openings with an enlargedliquid containing reservoir therebetween, and a circuit opening meansimmersed and arranged to draw an arc in said liquid in said chamber,said chamber and said circuit opening means being so arranged that uponthe drawing of the arc, two arcs in series are produced substantiallysimultaneously in said two small openings of said chamber with one ofsaid arcs producing a fluid blast from said reservoir to extinguish saidother arc.

8. An electric circuit interrupter of the fluid blast type comprising anarc chamber containing an arc extinguishing liquid, said are chambercomprising means defining two relatively amazes small openings with anenlarged liquid containing reservoir there between, said openings diiiering dimensionally from each other, and a cirrig means immersed andarranged to aw in said liquid in said chamber, said chamber and saidcircuit openng means being so arranged that upon the drawing of the arc,two arcs in series are produced substantially simultaneously in said twosmall openings of said chamber with one of said arcs producing a fluidblast from said reservoir to extinguish said other arc.

9. An electric circuit interrupter of the fluid blast type comprising anarc chamber containing an arc extinguishing liquid, said arc chambercomprising means defining two relatively small openings with an enlargedliquid containing reservoir therebetween, a circuit opening meansimmersed and arranged to draw an arc in said liquid said chamber, saidchamber and said circuit opening means being so arranged that upon thedrawing of the arc, two arcs in. series produced substantiallysimultaneously in said two small op nin s of said chamber, and means forproduca dfierential in the relative pressures genmeans, a verticallyremovable carrier for said circuit opening means mounted in said cas nl.a cylindrical arc chamber supported in said carrier, an arcextinguishing liquid in said casing and in said chamber, and meansdefining a pair of vertically spaced openings one at each end of saidchamber so the head of said liquid above the lower 01' said openings isgreater than above the other of said openings, said circuit openingmeans being immersed and arranged to produce an arc in said liquid insaid chamber, said chamber and said circuit opening means being soarranged in said carrier that upon the production of said are two arcsin series are produced substantially simultaneously in said'two openingswith the arc in said lower opening producing a fluid blast through saidupper opening to extinguish said other arc in said upper opening.

RALPH S. BENNETT.

REFERENCES CITED The following references are of record in the file oithis patent:

UhI'lED STATES PATENTS Number Name Date 2,049,318 Prince July 28, 1938Re. 20,450 Hill July 20, 193'! 2,185,039 smith Dec. 26, 1939 2,337,872Craig Dec. 28, 1943

